Emissions sources produce exhaust that may contain one or more pollutants. For certain circumstances, it may be beneficial to control pollutant that proceeds to the environment. In order to control pollutants, the amount of pollutant contained with exhaust gases proceeding is monitored.
In general, the conditions within or near an exhaust passageway may be adverse and/or harsh. For example, elevated temperatures may be present. As another example, the corrosive agents may be present in the exhaust gases.